BY C. W. DE VIS. 



119 



To acquire a definite notion of the extent to which the bird 

 ulna varies in its proportions, the writer has prepared a tabular 

 statement of the extreme length and minimum breadth of the bone 

 from measurements of it in ninety-eight representatives of the 

 larger sections of Australian birds ; and from the measures of 



length and breadth has by the use of the formula, 



transverse 



xlOO, 



longitudinal 



derived an index which may be called the ulnar index. By this 

 proportions may be conveniently estimated, slenderness increasing 

 as the index diminishes. The lengthiness of the entire table 

 prohibits its introduction here ; a summary may, however, be 

 given if accompanied by the warning that in some families the 

 indices are derived from one or two species only. 



Table of Ulnar 



FalconidsB 



Strigidse .„. 



Corvidaa ... 



Paradiseidee 



Oriolidse ... 



Campophagiclse 



Menu rid ae 



Ptilonorhynchidse .. 



Cuculidae 



Alcedinida? 



Caprimulgidse 



Coraciadse 



Psittaci 



Columbae 



Megapodidse 



OtidicUe ... 



Rallidae ... 



Charadriidse 



Ardeidse ... 



Anatidse... 



Pelecanid ee 



Steganopodes 



Podicipitidse 



Indices in Birds. 



